[PATCH] arm: fix build with gcc 4.7.x

[PATCH] arm: fix build with gcc 4.7.x

[Jan Beulich]

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As was already pointed out months ago (see
http://lists.xen.org/archives/html/xen-devel/2012-02/msg00826.html),
gcc 4.7.x (imo validly) refuses to take both -mcpu=cortex-a15 and
-march=armv7-a due to conflicting feature sets causing amibiguity in
instruction selection. Since the former implies the latter, just use
the former (and drop the -march=).

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -24,7 +24,7 @@ ifneq ($(call cc-option,$(CC),-fvisibili
 CFLAGS += -DGCC_HAS_VISIBILITY_ATTRIBUTE
 endif
 
-CFLAGS += -march=armv7-a -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
+CFLAGS += -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
 
 # Require GCC v3.4+ (to avoid issues with alignment constraints in Xen headers)
 check-$(gcc) = $(call cc-ver-check,CC,0x030400,"Xen requires at least gcc-3.4")




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arm: fix build with gcc 4.7.x

As was already pointed out months ago (see
http://lists.xen.org/archives/html/xen-devel/2012-02/msg00826.html),
gcc 4.7.x (imo validly) refuses to take both -mcpu=cortex-a15 and
-march=armv7-a due to conflicting feature sets causing amibiguity in
instruction selection. Since the former implies the latter, just use
the former (and drop the -march=).

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -24,7 +24,7 @@ ifneq ($(call cc-option,$(CC),-fvisibili
 CFLAGS += -DGCC_HAS_VISIBILITY_ATTRIBUTE
 endif
 
-CFLAGS += -march=armv7-a -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
+CFLAGS += -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
 
 # Require GCC v3.4+ (to avoid issues with alignment constraints in Xen headers)
 check-$(gcc) = $(call cc-ver-check,CC,0x030400,"Xen requires at least gcc-3.4")

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Re: [PATCH] arm: fix build with gcc 4.7.x

[Ian Campbell]

On Mon, 2012-06-25 at 11:57 +0100, Jan Beulich wrote:
> As was already pointed out months ago (see
> http://lists.xen.org/archives/html/xen-devel/2012-02/msg00826.html),
> gcc 4.7.x (imo validly) refuses to take both -mcpu=cortex-a15 and
> -march=armv7-a due to conflicting feature sets causing amibiguity in
> instruction selection. Since the former implies the latter, just use
> the former (and drop the -march=).
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

> 
> --- a/xen/arch/arm/Rules.mk
> +++ b/xen/arch/arm/Rules.mk
> @@ -24,7 +24,7 @@ ifneq ($(call cc-option,$(CC),-fvisibili
>  CFLAGS += -DGCC_HAS_VISIBILITY_ATTRIBUTE
>  endif
>  
> -CFLAGS += -march=armv7-a -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
> +CFLAGS += -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
>  
>  # Require GCC v3.4+ (to avoid issues with alignment constraints in Xen headers)
>  check-$(gcc) = $(call cc-ver-check,CC,0x030400,"Xen requires at least gcc-3.4")
> 
> 
> 

Re: [PATCH] arm: fix build with gcc 4.7.x

[David Vrabel]

On 25/06/12 11:57, Jan Beulich wrote:
> As was already pointed out months ago (see
> http://lists.xen.org/archives/html/xen-devel/2012-02/msg00826.html),
> gcc 4.7.x (imo validly) refuses to take both -mcpu=cortex-a15 and
> -march=armv7-a due to conflicting feature sets causing amibiguity in
> instruction selection. Since the former implies the latter, just use
> the former (and drop the -march=).

Given that we currently use the v7-A envelope model rather than a
Cortex-A15 I think -march=armv7-a is the correct option.

David

> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> --- a/xen/arch/arm/Rules.mk
> +++ b/xen/arch/arm/Rules.mk
> @@ -24,7 +24,7 @@ ifneq ($(call cc-option,$(CC),-fvisibili
>  CFLAGS += -DGCC_HAS_VISIBILITY_ATTRIBUTE
>  endif
>  
> -CFLAGS += -march=armv7-a -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
> +CFLAGS += -mcpu=cortex-a15 -mfpu=vfpv3 -mfloat-abi=softfp
>  
>  # Require GCC v3.4+ (to avoid issues with alignment constraints in Xen headers)
>  check-$(gcc) = $(call cc-ver-check,CC,0x030400,"Xen requires at least gcc-3.4")

Re: [PATCH] arm: fix build with gcc 4.7.x

[Jan Beulich]

>>> David Vrabel <david.vrabel@citrix.com> 07/03/12 7:09 PM >>>
>On 25/06/12 11:57, Jan Beulich wrote:
>> As was already pointed out months ago (see
>> http://lists.xen.org/archives/html/xen-devel/2012-02/msg00826.html),
>> gcc 4.7.x (imo validly) refuses to take both -mcpu=cortex-a15 and
>> -march=armv7-a due to conflicting feature sets causing amibiguity in
>> instruction selection. Since the former implies the latter, just use
>> the former (and drop the -march=).
>
>Given that we currently use the v7-A envelope model rather than a
>Cortex-A15 I think -march=armv7-a is the correct option.

Which would mean passing the -mcpu= was wrong from the start.
I'll leave this to the ARM maintainers in any case, the purpose of the
change was merely to get the thing to build again.

Jan